Method and apparatus for embedding and detecting watermark

Abstract

A method of embedding a watermark in video data includes generating a watermark to be embedded in the video data, generating a bit string based on a generated watermark, and embedding a watermark in the video data by changing a quantization parameter of the video data by a predetermined value based on the bit string.

What is claimed is: 
     
         1 . A method of embedding a watermark in video data, the method comprising:
 generating a watermark to be embedded in the video data;   generating a bit string based on a generated watermark; and   embedding a watermark in the video data by changing a quantization parameter of the video data by a predetermined value based on the bit string.   
     
     
         2 . The method of  claim 1 , wherein the embedding of a watermark comprises dividing the video data into a plurality of areas having a predetermined size and changing a value of a quantization parameter corresponding to the plurality of areas to allow a bit included in the bit string to correspond to one of the plurality of areas. 
     
     
         3 . The method of  claim 2 , wherein one of the plurality of areas is a pixel block having a predetermined number of pixels and belonging to one or more continuous frames in a group of pictures. 
     
     
         4 . The method of  claim 1 , wherein the quantization parameter is a quantization parameter of a chroma component of the video data. 
     
     
         5 . The method of  claim 1 , wherein the embedding of a watermark comprises changing an offset value of the quantization parameter. 
     
     
         6 . The method of  claim 1 , wherein the embedding of the watermark comprises changing the quantization parameter by decreasing the quantization parameter. 
     
     
         7 . The method of  claim 1 , wherein the embedding of the watermark comprises changing a plurality of quantization parameters to correspond to a plurality of bits in the bit string. 
     
     
         8 . A computer-readable recording medium having recorded thereon a program for executing the method of embedding a watermark of  claim 1 . 
     
     
         9 . A method of detecting a watermark embedded in video data, the method comprising:
 determining whether a quantization parameter is changed in the video data where the watermark is embedded;   determining a bit string based on the determination of whether the quantization parameter is changed in the video data where the watermark is embedded; and   restoring the watermark from a generated bit string.   
     
     
         10 . The method of  claim 9 , wherein, in the determining of whether a quantization parameter is changed, the video data where the watermark is embedded is divided into a plurality of areas having a predetermined size and whether the quantization parameter of each of the plurality of areas is changed is determined. 
     
     
         11 . The method of  claim 10 , wherein one of the plurality of areas is a pixel block having a predetermined number of pixels and belonging to one or more continuous frames in a group of pictures. 
     
     
         12 . The method of  claim 9 , wherein the quantization parameter is a quantization parameter of a chroma component of the video data. 
     
     
         13 . The method of  claim 9 , wherein the determining of whether the quantization parameter is changed comprises determining whether an offset value of the quantization parameter is changed. 
     
     
         14 . The method of  claim 9 , wherein the determining of whether the quantization parameter is changed comprises comparing the video data where a watermark is embedded with the original video data and the video data where a watermark is embedded with video data where a quantization parameter of the original video data is changed; and
 determining whether a quantization parameter is changed based on a result of the comparisons.   
     
     
         15 . The method of  claim 14 , wherein the video data where the quantization parameter of the original video data is obtained by decreasing the quantization parameter. 
     
     
         16 . The method of  claim 9 , wherein the determining of whether the quantization parameter is changed comprises determining whether a plurality of quantization parameters are changed. 
     
     
         17 . A computer-readable recording medium having recorded thereon a program for executing the method of detecting a watermark of  claim 9 . 
     
     
         18 . An apparatus for embedding a watermark in video data, the apparatus comprising:
 a watermark generator which generates a watermark to be embedded in the video data;   an encoder which generates a bit string based on a watermark generated by the watermark generator; and   a watermark embedder which embeds a generated bit string in the video data by chaining a quantization parameter of the video data by a predetermined value.   
     
     
         19 . The apparatus of  claim 18 , wherein the quantization parameter is a quantization parameter of a chroma component of the video data. 
     
     
         20 . The apparatus of  claim 18 , wherein the watermark embedder changed an offset value of the quantization parameter. 
     
     
         21 . The apparatus of  claim 18 , wherein the watermark embedder divides the video data into a plurality of areas having a predetermined size and changes a value of a quantization parameter corresponding to the plurality of areas to allow a bit included in the bit string to correspond to one of the plurality of areas. 
     
     
         22 . An apparatus for detecting a watermark embedded in video data, the apparatus comprising:
 a determination unit which determines whether a quantization parameter is changed in the video data where the watermark is embedded;   a bit string generator which generates a bit string based on the determination of the determination unit; and   a decoder which generates a watermark from a generated bit string.   
     
     
         23 . The apparatus of  claim 22 , wherein the determination unit determines whether the quantization parameter is changed by comparing the video data where a watermark is embedded with the original video data and the video data where a watermark is embedded with video data where a quantization parameter of the original video data is changed. 
     
     
         24 . The apparatus of  claim 23 , wherein the determination unit divides each of the video data where the watermark is embedded, the original video data, and the video data Where the quantization parameter is changed into a plurality of areas having a predetermined size and compares data for each divided area. 
     
     
         25 . The apparatus of  claim 24 , wherein one of the plurality of areas is a pixel block having a predetermined number of pixels and belonging to one or more continuous frames in a group of pictures. 
     
     
         26 . The apparatus of  claim 22 , wherein the quantization parameter is a quantization parameter of a chroma component of the video data. 
     
     
         27 . The apparatus of  claim 22 , wherein whether the quantization parameter is changed is determined by whether an offset value of the quantization parameter is changed.